I called online shop and they informed me that the intake for IS F would fit RC F. Makes senses as
that is essentially the same engine but tweaked in RC F form. Anyone able to confirm Fitment?

Though I know the stock filter has the open flap at higher rpm so not sure how much more gains would be had by going open filter like K&N or Takeda, any thoughts?

 

The throttle body is larger in the rcf. The coupler with any isf intake needs to be able to stretch .25 or .50 of an inch more. Most people haven't any issues